Dawn of the Tiberium Age (DTA) is a stand-alone mod that combines Tiberian Dawn (C&C 95) and Red Alert. While classic mode gets as close to the original game-play and balance as possible, Enhanced mode provides improved game balance and a lot of fun new stuff.
DTA features many customization options for Skirmish and multiplayer (where you can play as GDI, Nod, Allies and Soviet on over 100 maps), challenging original singleplayer missions, as well as co-op missions.
Since this is a stand-alone mod, you don't require anything but the mod itself to be able to play: the original game is not required.

The Dawn of the Tiberium Age version 1.12 has been released over just 2 months ago already and quite a few updates have been released since then, including the update to version 1.1228 that was released today.

I'll quickly summarize the most important changes after version 1.12:

Many performance issues have been fixed, which caused the game to slow down, crash or even not start at all.

Small issues on a number of maps have been fixed.

More changes to make DTA's classic mode match Tiberian Dawn even more closely have been made.

Many balance improvements have been made, which make battles between different factions more fair and enjoyable.

Players used to be unable to join hosted games on CnCNet, unless it was the first game in the list. This meant that if someone hosted a game after you hosted one, nobody would be able to join your game anymore (this is one reason why some players ended up waiting for hours for someone to join, with no one ever entering it).

Alliances wouldn't be set up properly when you'd attempt to play with more than 4 players in a single team.

All Red Alert units now use voices and weapon sounds from Red Alert (the light infantry and rocket infantry still used American voices before), while the Tiberian Dawn units still use their original sounds. All tanks currently still use the firing sounds from Tiberian Dawn, although you can replace these tank firing sounds with the Red Alert variants via a checkbox in the options menu (this option will also change the sound you hear when a building is destroyed to the Red Alert variant).

All factions are now able to repair their aircraft on the Repair Facility (Allies and Soviet weren't able to before).
The game engine actually only allows aircraft to be repaired on a single Repair Facility, so to get around this, all factions now build the same Repair Facility and its graphics will either look like the Tiberian Dawn or the Red Alert version depending on the faction you're playing as. As a side-effect you can now see a Red Alert Repair Facility in a GDI base for example and it was also necessary to make Nod able to build the Repair Facility as well.

It turns out that the King of the Hill mode wasn't properly playable because the timer only functioned when playing as Allies. This has now been fixed, so if you've tried this game mode before and it didn't work, please give it another shot.

Because of a small error in the launcher's code, Soviet would never be picked whenever you selected Random as your faction; this has now been fixed.

Capturing construction yards or refineries of other factions should no longer make unclickable grey icons appear on the sidebar.

You can no longer play as Allies or Soviet in Classic mode; you can still select them, but this will now make you start as either GDI or Nod with a Red Alert sidebar; the Red Alert factions have a huge unfair advantage in classic mode after all. This is a temporary solution until the option to select the Red Alert factions is completely removed whenever classic mode has been selected.

The multiplayer map "Perilous Islands" has been added, which can be seen in the image below. This map is unique in the sense that you purely need to rely on ships and aircraft in order to win the match and also capturing islands in order to boost your economy. The AI will be a tough opponent on this map as well.

As you can see, quite a few changes have been made in these past 2 months already, so if you've had issues before and you haven't updated recently, try the latest version and chances are that your issues have been solved. If not, please don't hesitate to report them (whether they're performance issues or gameplay issues) and we'll fix any issues that are within our power to fix, as soon as possible.

My browser has an automatic spell-checker and it has picked up no typos other than a few words that it simply doesn't know (such as "unclickable" or "tiberium"). Feel free to point out any parts you think are wrong or don't understand however; I'll either correct them if they really are wrong or I'll explain what you didn't understand.